Determining the effective magnetic Hamiltonian and the ground state properties of FePS3

Two-dimensional (2D) magnetism has drawn attention due to its properties distinct from those in three-dimensional magnetic systems. One of the most notable features is the Mermin-Wagner theorem, which states that with isotropic Heisenberg interactions, long-range magnetic order cannot exist at finite temperatures in a 2D system. Despite the Mermin-Wagner theorem, long-range magnetic order can still arise due to magnetic anisotropy. To understand 2D magnetism, extensive studies have been focused on establishing a model Hamiltonian for various materials. It is essential to develop an accurate magnetic energy model not only to characterize the ground state but also to explain phase transitions or low-energy excitations such as spin waves. In this study, we focus on the magnetism of monolayer FePS3. We calculate total energies and magnetic moments of various spin configurations to determine the Hamiltonian. We then conduct a quantitative analysis of the magnetic anisotropy and of the exchange interactions and discuss how FePS3 achieves its known ground state, the zigzag-type antiferromagnetism. [1,2].



[1] T. Y. Kim, and C.-H. Park, Magnetic Anisotropy and Magnetic ordering of Transition-Metal Phosphorus Trisulfides, Nano Lett. 2021, 21, 23, 10114–10121

[2] M. Ghim, T. Y. Kim, C.-H. Park, unpublished